Morton lea adams



Patented J uly 8, 1919 LIIIIIIIIIIIIFET M. L. ADAMS. TRACTOR ATTACHMENT FOR MOTOR VEHICLES APPLICATION FILED JULY 26,1918.

. Arron/vers Ll 'I M. L. ADAMS. TRACTOR ATTACHMENT FOR MOTOR VEHICLES. APPLICATION FILED IuLY 26.1918.

1,309,053, Patentd July 8, 1919.

2 sHhETs-SHEEI 2.

UisiTED sTATEs PATENT oEEicE MORTON LEA-ADAMS, OF SEATTLE, WASHINGTON, ASSIG-NOR TO ADAMS TRACTOR COMPANY, OF SEATTLE, WASHINGTON, A CORPORATION OF WAS'HTNGTON.

TRACTOR ATTACHMENT FOR MOTOR-VEHICLES.

Speeiiication of Letters Patent.

Patented July 8, i919.

Application led July 26, 1918. Serial No. 246,931.

structions, combinations and arrangements herein described and claimed.

An object of my invention is to provide primarily a tractor `designed -principally for farm work and consequently one of a rugged construction, which embodies means residing in the tractor attachments whereby the tractor can lbe turned within its own length simply by the manipulation` of the braking devices.

Another object otv the inventionis to provide a tractor attachment which em` bodies a compensating or diierential gear `whereby a uniform driving torque is ap` plied to the axles at both ends.

A further object of the invention is to provide a tractor attachment wherein the construction of Athe vsupporting elements whereby 'the attachment is hung in place, may be readily altered t0 adapt it to axle mountings of the full, three-quarter or semifloating types.-

A further object of the invention is to provide a braking mechanism of a novel construction for coperation with the brake drums of the differential drive axles, which includes a brake jack shaft with a differential gear embodied therein to enable either the locking of both brakes or the locking of but one. 4

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawings in which:

Figure 1 is a horizontal section of the improved tractor.

Fig. 2 is an enlarged detail section showthe extremity of the axle,

ing the differential or compensating gear of one of the tractork attachments,

Fig. 3 is a detail sectional view of one of the tread driving sprockets and a portion of the improved tractor belt, I

Fig. 4. is a longitudinal section of one of the tread links,

Fig. 5 is a plan view of one of the tread links a part being shown in section, and l Fig. 6 is an end elevation of one of the inks.

The present invention is an improvement oir the subject matter of my co-pending application for a patent on tractor attachments, filed April 20, 1918, Serial No. 229,774. The improvement lies more particularly in the driving means for the tread driving sprockets at the ends of the attachment, and in order that the relationship oi the two inventions may more readily be understood,

- A synopsis of the former construction is here outlined.

The construction 4in the former application involves a driven axle which projects beyond an axle casing. An axle housing 1s litted on the axle casing and includes an extension support which is applied directly to a yoke in the axle housing enables the fitting'of a pair of in` tegrally formed driving sprockets on the axle. The present improvement consists. of the replacing of these integral driving sprockets, with a differential drivinggear so that the driving torque is appliedy uniformly to the axles at both ends of the attachment.

The improved tractor attachment tion of the attachment. One member of" a two-part drive axle 1 projects into each of the two tractor attachments 2 and provides the mounting or the tractor attach-- ment on the tractor body 3.

Frames 7 and 8 inside of the tractorI at- I ings 'are' j ournaled Aon tachment 2 are spaced apart as illustrated, and have hubs 9 in the middle through owhich the supporting members extend. The axle casing 10 extends into the tractor attachment where it enlarges into a hub which has an annular rib 11. The rib 1l fits in a groove 12 in the hub 9 of the frame 7 and thus prevents the frame from sliding olf. The drive axle l has a ball bearing on the inside of the axle casing hub and there is a second ball bearing between the drive axle and the outer frame 8. This is a mounting of the well-known semi-floating type.

While the drawings `do not disclose'the three axle mountings usually employed in automobile manufacture namely, the full,

three-quarter and semi-floating types, yet I- wish to make it understood that the tractor attachment o2 can be mounted by using any of the three types by making but minor changes. It is not deemed necessary either to illustrate or describe all three mountings, it being thought suiicientto show but the semi-floating drive axle mounting referred to above.

Resuming the description of the tractor attachment, axles 15 are journaled in the 4ends of the frames 7 and 8. Suitable ball bearings are provided for the axles. Pairs of idler wheels 16, 17 are mountedon the axles 15 at the front and rear of the attachment. In this construction asin that of the former invention, it is important that these idlervwheels be peripherally grooved. It is important that V-grooves be used -in order that but a minimlmdamount of friction occurs in engaging an isengaging.

Mounted on the axles 15 between the/bearof the frames 17, are sprocket hubs 18. The hubs of the axles at the front and rear respectively, 27, 28. These driving sprockets are in longitudinal alinement and in the center of the tractor attachment 2. Fixed on the hubs 18 and on opposite sides of the respective tread driving sprockets, are driven sprockets 25, 26 to which drive chains 23 and 24 are applied. These chains are driven by the differential gear mechanism on the drive" axle 1, which constitutes one of the important improvements and which will `be described later. J

The tread driving sprockets which are both alike, are different from those shown in the former construction in that the rollers 43 are carriedby the sprockets nstead of by the tread links. The rollers 43 pins 41 in the bifurcations 42 which are arranged at on the periphery of the tread) ets as shown in Fig. 3.

This arrangement of the tread driving sprockets obtains a rolling action of the driving sprockcarry tread driving sprockets v roper intervalsy teeth of the sprockets over the teeth of the tread links with which they engage. The manner of contact 'between the two is illustrated in Fig. 3 wherein it is to be observed that the engagement between the two occurs only on the driving side. As a result, there is a clearance between the remainder of the parts and vtherefore friction is eliminated to a considerable degree'.

Sets of grooved sheaves which are disposed on the inside and outside of the frames 7 and 8 respectively, are mounted on shafts which are supported near the lower edges of the frames. a purpose of keeping the lower strand of the tread in a straight line and to prevent it from buckling.' kling of the lower strand of the tread is necessary so that there can 'be no binding'b'etween the lower edges of the side plates 47 and the recesses 57 of the tread links, which are occupied by the side plates.

In this connection it is desirable to say that the lower edges of the side plates are formed with plow kerfs similarly as in the other construction, for the purpose of plowing out dirt accumulatedby the edges of the tread,

struction just referred to.

' Thev djferential dri/ve mecw/m'sm comprises sprockets 13 and 14 upon .which segmental bevel gears 20 and 21 are formed on the opposing sides. lnwardly vprojecting lugs 22 which are practically extensions of the bevel gears, are adapted to engage the bevel pinion 37 inthe event of a breakage of one of the) drive chains 23, 24. It will be readily understood that were it not for the provision of the lugs 22, upon the lbreakage of one of the drive chains referred to, the tractor attachment would be rendered inoperative since the bevel pinion 37A would merely travel around with the drive axle 1 running on the bevel gear of the with the intact drive chain, and simply counter-rotating the then free sprocketof .the broken chain.

The prevent-ion of the buc-` sprocket These sheaves are for the the tractor attachment is not rendered inoperative sincefthe driving of one of the driven sprockets 25, 26 still continues.

A spider 44 which is nothing more than ahub keyed on the drive axle 1, provides the support for the bevel pinion l37. Under normal conditions, the bevel pinion has but very' segments.

'segments 20, 21. It is not until one of the drive chains is broken, that the bevel pinion moves to any extent relative to these gear The spider 44 has reduced bearings upon which the sprockets 13 and 14 are loosely mounted. The ends of the bearings are threaded to receive check nuts 45 which hold'the sprockets in place.

The improved tread Zink at 31 on the ends at opposite sides as clearly y shown in Fig. 5. The remaining leaves 32 engage the companion leaves of another tread link and occupy the cut away portions of the rail portions of the companion tread link, so that the continuous tracks referred to are provided. A pair of knuckles 33 on one transverse edge of the tread link,

embrace a single knuckle 34 on the transi Y verse edge of another tread link.

A hinge pin 35 holds the links together. The hinge pin has a drivingtit in the bores of the knuckles 33. A bushing 36 in the j larger bore of the single knuckle'34, provides the swinging connection of .one knuckle on the other. A tooth 38 is formed in the middle of each tread link. Each tooth consists of a pair of upward projections with an `intervening valley into which the sprocket roller 43 advances'v when the engagement of the tread driving sprocket with the tractor belt occurs.

The manner of contact between the sprocket roller and the tractor belt -has already been described in connection with Fig. 3, but it may be repeated briefly that the engagement of the roller with the tooth occurs only on one side. Considerable friction is avoided by the freedom of the remaining j surfaces. The tread link has, Whatmight be termed, a skeleton formation. The exposed wallmay be made as thick as desired so as to give the required strength. This wall terminates in ridges 39 inside of the knuckles, and these ridges rigidify the tread link transversely. The exposed surface it# self may be of any desired shape, so long as the advantage of making the tread link as a drop forglng, is preserved. The longitudinal edges 40 of the tread link extend tread link is such thatv the respective members, enable the beyond the extreme rail portions and form the recesses 57 which are occupied by the side plates.

' The tracto/r body 3.

bearings inthe tractor body and incloses the bevel gears 5 which are fixed on the ends of the members of the two-part drive axle 1. Bevel pinions 6 carried by the case 4 engage the gears '5. This construction constitutes an ordinary differential gearing.

The axle 1 is driven by means of a spur pinion 46 which meshes with a spur gear 48 on the dierential case 4.- The gear 48 is in the nature of a ring which is fitted on the periphery of the joint of the gear' case. f A number of holes are bored transversely of the gear ring in the middle of the joint,"and the bolts which are theninserted hold the gear in place. The spur pinion 46 may bc driven by any suitable power, a steam engine 49 being diagrammatically illustrated in Fig.` 1.

Brake drums 50 are lixed on the members of the drive axle 1. A brake band on each drum is arranged to be contracted by means of ya knuckle 51 to which a link 52 is connected. -Each link 52 reaches rearwardly and is connected to one member of a twopart brake jack shaft 53. Handles 54 on locking ofthe individual brake drums; that is to Say one brake drum may be locked independently of the other. It is by this arrangement that the tractor is steered and can be turned within its length.

A dierential gearing 55 joins the members of the jack shaft, and-the casing of the gearing hasa pedal 56. When it is desired to lock both brake drums so as `to brake the tractor, the operator presses on the pedal In order to prevent lateral strains on the drive axle 1 in turning the tractor, the inner ends of the axles 15 are made to project through the inner side p lates 47, and are provided with spring blocks 58. Semielliptic springs 59 are fastened on the top and bottom of each spring block. Stops 60 fixed on the sides ofthe tractor body 3, project between the free ends ofthe springs 59. The arrangement of the stops and springs allows a certain amount of oscillating motion of the tractor attachment on the drive axle 1 and in a measure, absorbs some 0f the shocks. j

Balls 61 held in bearings 62 .carriedA on the inner ends of the axles 15,

body 3 and on the drive axle 1 by maintaining an even space.

The operation.

While the operation of the tractor and the tractor attachmentson the sides thereof is thought to be fully understood from the foregoing, yet a. brief reviewis thought to be of advantage. It may be stated in passing, that the tractor body 3 in actual practice may be provided with wheels atthe front so that the tractor is capable for use in road work. The present illustration,

however, omits the showing of the wheels, e since as stated above their addition is merely an incidental feature.

The foremost feature in the tractor, resides in the manner of steerin it. Under ordinary conditions the brake rums 50 are free and consequently the members of'Y the two-part drive axle 1 are rotated in unison so that the .i tractor proceeds forwardly. i Should it now be desired to' make a turn,

vone or the other ofthe handles 54- are pushed forwardly when the corresponding brake band locks on the companion brake drum causing the bevel gear 5 to remain stationary. The other tractor attachment continu.

mg to move, causes the turn to be made. Should it be desired to brake the forward movement of the tractor, the pedal 56 is de- A. pressed and` both brake drums are locked together.

It'. has been found in actual experience that in order to obtain a uniform driving vaction of the ltread drive sprockets 27, 28

y at both endsof the tractor attachment, itl is absolutely necessary to provide the differen- I tll drive mechanism illustrated in Fig. 2.

sprockets 13 and 14 are susceptible lof in 40 respect A. to each other under ordinary circumstances, compensates for the ordinary inability topproperly aline the drive chains on the drive sprockets and the companion driven sprockets as is the case in the former construction above referred to. -The differential drive mechanism' causes the drive chains 23, 24 to adapt themselves directly to the driven sprockets 25, 26 so that the power is applied t-oboth sprockets 27 and 28. The

0 importance of this arrangement lies in the act that excessive wear on the tread link hinge pins isprevented and also in that uneven str'ains on the tread belt are prevented.

, The tractor attachment is not disabled al- .'55 together in the event that one of the drive chains breaks. 'This of course is an uncommon, occurrence butA should it happen that lone of the chains break, the lugs 22 will en- A gage the pinion 37 and cause the two sprocky ets 13, 14 to rotate together so that tho -.d

tractor attachment end `or the other. While the construction and arrangement of the evice as herein described and claimed is driven either at one Y is that of a 'genera `pensating for disalinement small relative movement to which the J lly preferred form, obviously modifications and changes may be made without departing from the spirit of the invention or 'the scope of the claims.

I claim y 1. A tractor attachment comprising an axle ,at each end, tread driving sprockets fixed on the axles, a drive axle, and means carried by the drive axle` having connection with. said axles and normally applying .power uniformly tothe tread driving sprockets to reduce the strain on the tread elements, said means including differential gearing on the drive axle.

2. Instrumentalities for uniformly applying power to both ends of a tractor attachment, comprising a drive axle, differentialv gear mechanism mounted on the drive axle, a tread drive sprocket at each end of the attachment, a tractor belt driven by said sprockets, and driving connections between said tread drive tial gearing, said .differential gearing comin the driving connections and insuring the power to both ends.

- Instrumentalities for preventing the disabling of a tractor attachment upon the lbreakage of a drive chain, comprising in combination a pair of driven sprockets, a drive axle, a differential gearing mounted on the drive axle comprising a pair of drive sprockets with gear portions, loose in respect to the drive axle, a pinion engaging the gear portions with a fixed the drive axle, drive chains applied to companion drive and driven sprockets, and lugs carried by the drive sprockets, engageable by the pinion upon the breakage of one of the drive chains, to cause the drive sprockets to move together and continue to drive application of mounting on.

sprockets and the diiferenone of the driven sprockets by the intact drive chain. e

4. pair of freely revoluble drivin sprockets, a drive axle on the axes of said sprockets, opposed gear portions on the sprockets, ay pinion meshing with the gear portions normally locking the drive sprockets together but enabling a limited relative movement of said sprockets thus constituting a differential gearing, a xedmounting for the pinion on the drive axle, drive chains applied to the drive sprockets for impart-I lng driving movement from the drive axle, and means including lugs extending from the drive sprockets into the plane of the pinion, to be engaged by the pinion upon the breaking of one of releasing the resistance on the companion rive sprocket, to lock the drive sprockets together.

5. A differential gear for impartinguniform driving movement to both ends of a tractor attachment, comprising a drive axle,

the drive chains and Y naoaoav aspider including bearin hubs with thread- `ed ends keyed on the rive axle, a j pinion j ournaled on a portion of the spider, driving sprockets loosely mounted on the hubs, with segmental bevel gear portions en; gaged by the pinion, means applied to the threaded portions for sprockets in place, and inwardly extending lugs formed on the sprockets and arranged to vbe engaged by said pinion under abnormal conditions. j

6. Means for mounting a tractor attachment, consisting of a relatively fixed axle casing enlarging into a bearing hub,y an annular rib on the hub, a drive axle extending Vthrough the axle casing and beyond the bearing hub, bearing means between the drive axle and the bearing hub, a frame with bearingmeans on the extremity of the drive axle, anda companion frame supported on the' bearing hub, with a recess receiving. the rib, preventing the frames from slipping off and enabling rocking motion thereof.

7 Means for mounting a tractor attachment on the side of a tractor body, con.

sisting of a relatively' fixed axle casing on the side of -said body enlarging into a bearing hub, an annular rib on the hub, a drive axle from the tractor body extending through the casing beyond the hub and having a b earing in the hub, a frame having bearing on the extremity of the drive axle, a companionv frame supported on fthe bearing hub, with a recess receiving the rib, preventing the frames rom'slippivng off and permitting rocking motion ofthe tractor attachment in respect to the tractor body, and means extending into engagement with the tractor body from the ends off'said attachment, to prevent lateraltwisting on the drive axle and to limit the rockingjmotio/n of the attachment.

SnMeans for preventing lateral twisting of a tractor attachment lon'a drive axle extendin from a tractor body, 'consistingof a pair o axles journaled in-a tractor lattachment, a pair of frames located inside of the attachment and supporting the axle, one of -said frames having a hub with anan'nular recess, a drive axle casing mounted on the.

side of the. tractor body and enlarging'into a bearing hub on theinside of the tractor attachment, an annular rib on the bearing hub fitting in said recess, permitting vertical rocking motion of said attachment but preventing 1t from slipping olf, and bearing bevelV holdingthe drivingl tractor body, spring teeth.

orted on' the means including rollers sup e side of the end of the axles, engaging t tractor body.

9. Means, for limiting the rocking motion of a tractor attachment in respect to a trac- 'tor body, consisting of a pair .of axles mounted near the ends of a tractor attachment and projecting toward the side of the blocks carried by said axles, semi-elliptic springs mounted on said blocks, .stops extending from the tractor body between the free ends of the springs,

and rollers mounted on the ends of the axles engagin the side of the tractor body. j

10. eans for steering a tractor by the manipulation of a pair of tractor attachments, consisting of a two-part drive axle extending into and forming the supports for said tractor attachments, means on the inside of each tractor attachment for driving it from the respective members of the drive axle,.a differential gearing at vthe juncture of the members of the drive axle, driving means applied to said gearing, a brake drum. L on each axle member, a drum,

brake band on each and means yfor locking the .bands either singly or together, prisin a two-part brake jack shaft, a dif*- erential gearing joining theparts, a foot said means comf .pedal embodied in. the dierential gearing eectln the simultaneous rotationl of both parts o the jack shaft, handles on each of the parts, and connections between said parts and the brake band.l

11. A. tractor attachment including va `tread belt consisting of tread links with interengaging knuckle joints forming aclosed hinge joint, rail, portions having cut away sides and leaves arran ed to inter'engageV to form continuous trac s, teeth formed m the tread links, and tread drive sprockets having roller teeth for engaging said link 12. A tread-link consisting of a body provided with transverse ridges to strengthen the link laterally, a'single -knuckle on one: edge, a pair of leaves, portions extending beyondA the. extreme rail sections to vprovide plate recesses,

MoRToN Lne ADAM-s.

lmuckles on the other edge arranged toaline with the single knuckle of v `and -a tooth. formed inv the middle of the tread p' 4. y 

